Attachment for grinding machines



Oct. 11, 1938. R. D. STREBY ATTACHMENT FOR GRINDING MACHINES Filed Feb. 2 1, 1938 /IIA u",- a; III/[,

5 Z/ /VTO Patented Get. 11, 1938 UNITED STATES PATENT OFFICE Application February 21, 1938, Serial No. 191,613

Claims.

My invention relates to grinding machines and the like of the type wherein two or more grinding wheels or tools are brought into operation in succession on the same work piece. The principal object of the present invention is to enable the second grinding wheel or tool to be attached and detached repeatedly without disturbing the setting of the first wheel and with the assurance that the second wheel will automatically take the precise position allotted to it. The invention consists principally in a detachable attachment adapted to be mounted rigidly on the end of the spindle, without disturbing the wheel held by the spindle collet, and itself adapted to hold a second wheel in axial alinement or otherwise suitably correlated with the first Wheel. It also consists in the parts and combinations of parts hereinafter described and claimed.

In the accompanying drawing, which forms 29 part of this specification and wherein like reference numerals refer to like parts wherever they occur,

Fig. 1 is a longitudinal sectional view of an attachment embodying my invention;

Fig. 2 is a similar longitudinal sectional view of said attachment mounted on the end portion of a spindle of a grinding machine; and

Fig. 3 is a longitudinal sectional view of the body of an injector nozzle for the grinding of which my invention is specially applicable.

The injector nozzle body illustrated in the drawing is typical of the work to which the present invention relates. This nozzle body has a main bore A, a pintle bore B and a tapered valve curacy both as to size and concentricity. In one specific case, the nominal diameter of the main bore A was .2362 inch and the nominal diameter of the pintle bore B was .078 inch and they were required to be concentric within .0004 inch.

Heretofore, it has been the practice to grind the cylindrical valve bore A and the conical valve seat C with a single beveled grinding wheel with a cylindrical body portion of suitable diameter and a conical front end of the angle required for said valve seat. After the main bore A and the valve seat C were ground, it was the practice to dismount the beveled grinding wheel from the spindle and to replace it with a second grinding 50 wheel of proper size to grind the pintle bore B. In the specific instance, the beveled grinding wheel would have a nominal diameter of .025 inch and the second grinding wheel would have a nominal diameter of .075 inch. In actual practice, it was very seldom that the mere attachment seat C which must be ground with the utmost acof the second wheel to the spindle resulted in positioning it with the requisite precision and consequently it was always necessary for the workman to check the position of the second wheel and to set it with the degree of precision required. According to the present invention, the mounting of the first wheel is not disturbed by the mounting and dismounting of the second wheel and, when the second wheel is once properly set, it will be restored with precision to its correct position as often as it is removed and remounted.

Referring to Fig. 2, I indicates the spindle of the grinding machine with a hollow boss 2 at its end which is split endwise into a concentric series of tapered spring fingers 3 adapted to grip the shank 4 of a beveled grinding wheel 5. The rear portion of the boss 2 has an external screw thread formed thereon adapted to closely fit the internal thread of a nut or sleevefi whose forward portion has a tapering bore adapted to bear against the conical portions of the spring fingers 3 and press them into engagement with the shank 4 of the'grinding wheel 5. Thus spring fingers 3 of the boss 2 and the sleeve '6 together constitute a collet of ordinary type. Likewise, the grinding wheel '5 is provided with a screw 1 which works in a screw thread provided therefor in an axial bore 8 of the shank 4, as in ordinary practice.

According to the present invention, the collet sleeve or nut 6 has'an exterior thread upon which works an adapter member 9. This adapter member is a hollow bell-shaped member with an interior thread that loosely fits the exterior thread of the collet sleeve 6. The large end I 0 of the bell is externally knurled to facilitate turning by hand and has a cylindrical bore in which accurately fits the end of the machine spindle l. The inside diameter of this large end is reduced at a distance less than the length of the collet thread, thereby forming a shoulder II which bears flatwise against the squared end of the machine spindle I. By this arrangement, the adapter member 9 may be engaged with the thread of'the collet sleeve 6 and turned thereon until its shoulder ll bears against the end face of the spindle l with its large end closely fitting circumferentially around said spindle end and thus centering said adapter member relative thereto.

The middle portion I2 of the adapter member 9 is long enough to enclose the beveled wheel 5 without touching it or disturbing its setting. The outer end of the adapter member 9 is an axial shank l3 or extension integral with the member.

other portions of said member and of small enough diameter to enter the nozzle body and provided in its end with a threaded bore [4 adapted to receive a screw I5 on which is mounted the second grinding wheel IS. The threaded bore 14 is accurately centered with the axis of the adapter member 9 and thus locates the second grinding wheel l5 precisely in the axis of said adapter At the same time, the axis of the adapter member is precisely located concentrically and in alinement with the'aXis of the spindle l by reason of its accurately fitting over the end portion thereof where it is held firmly bythe I threaded engagement that holds its shoulder ll tight against the end face'of said spindle.

In practice, the shank 4 of the beveled grindbore A and the'valve seat C of the nozzle body are then ground with the beveled wheel 5, whereupon the adapter member 9 is mounted on the collet sleeve and screwed home against the end face of the spindle with its large end closely fitting the large diameter thereof. The pintle bore B is then ground with the second grinding wheel Hi. When the second grinding wheel 16 is once precisely positioned, the adapter member 8 can be removed as often as required with the assurance thatthe second grinding wheel IE will require no further attention to restore it to its exact position. Thus, after the two grinding wheels are correctly adjusted, no furtherv setting thereof is required until they become worn enough to require redressing or truing.

While I havedescribed my invention as applied to the grinding of injector nozzle bodies, I do not wish to be restricted thereto, as the invention is applicable to the grinding of other bodies and to operations with other tools.

What I claini is: j

l. The combination with a spindle having means adapted to hold a grinding wheel in axial alinement therewith, said means including a nut with screw threads on both its inner and outer surfaces, of a second means for holding another grinding wheel in axial alinement with said spindle, said second means comprising an adapter sleeve which fits circumferentially around the end portion of the spindle and against the end face of the spindle and which has a screw thread engaging the exterior thread of said, nut, said second means enclosing said first-mentioned wheel and supporting the second-mentioned wheel at its end.

2'. The combination of a spindle having a collet, a grinding wheel held by said collet in axial alinement with said spindle, said collet including a nut with screw threads on both its inner and outer surfaces, means for holding another grinding wheel in axial alinement with said spindle, said means comprising a bell-shaped member Whose end fits circumferentially around the end portion of the spindle and is provided inside with a shoulder adapted to bear against the end face of the spindle, said adapter member also having a screw thread engaging the exterior thread of said nut, said adapter member enclosing said first-mentioned Wheel and supporting the second-mentioned wheel at its end and in axial alinement with said spindle.

3. The combination of a spindle having means for holding a tool beyond the end of said spindle, a tool said holder, said means including an exterior screw thread and a second tool holding means adapted to hold a second tool vfurther beyond the end of said spindle, said second means comprising a bell-shaped member whose end fits circumferentially around the end portion of the spindle andis provided inside with a shoulder adapted to bear against the end face of the spindle, said adapter member also having a screw thread engaging said exterior thread, said bellshaped member enclosing said first-mentioned tool and supporting the second-mentioned tool at its end. v

4. An attachment for a grinding machine, said attachment comprising a bell-shaped member having an internal thread at one end and a grinding wheel support extending axially from the other end and having a grinding Wheel in axial alinement with said internal thread, and a collet nut having an external thread fitting the internal thread of said bell-shaped member and having an internal thread adapted for cooperation with a spindle member.

5. An attachment for a grinding machine, said attachment comprising a, bell-shaped member having an internal thread in its large end portion and an axially located shank extending longitudinally outward from the other end and a grinding wheel supported by said shank in axial I alinement with said internal thread.

RAY D. STREBY. 

